The present invention relates to lock nuts having a plurality of resilient locking segments which deflect in a manner similar to that of a beam, and, more particularly, to a construction of the locking segments wherein the internal threads at the junction of adjacent beams are angled radially inward, thereby forming a V-shaped internal slot. The present invention also is directed to a new method of manufacturing the lock nut.
The present invention is an improvement in the design of a locking beam nut described and disclosed in U.S. Pat. No. 5,088,868. The locking beam nut of the '868 patent discloses a design having a plurality of circumferentially-spaced resilient locking beams that were specifically configured to prevent any accumulated debris from preventing a desired deflection of the beams. The beams project from a substantially rigid body and have a circular opening extending completely through the body and the locking beams. The beams all taper inwardly, such that the circular opening they define have a uniformly decreasing diameter. Continuous threads of substantially uniform depth are defined in the aligned openings, for receiving an externally threaded member, wherein the locking beams resiliently deflect outwardly to lock the member in place. The confronting sidewalls of adjacent beams are configured to diverge outwardly from each other, such that any debris located between them could not inhibit inward deflection of the beams upon removal of the externally threaded member.
Although the design described in the '868 patent was an improvement upon prevailing locking beam nut designs, all previous designs for slotted beam nuts possess beams that are curved which, through natural stiffening of a curved design of a beam, have a tendency to concentrate loads and cause stress risers at the attachment points of the beams to the body of the nut. Consequently, low reuse cycles and rapid deterioration of the prevailing torque is undesirable. Another problem with previous beam nut designs is that typically the nut, which is utilized with a bolt having a holdout spring, compresses the spring when rotated in the internal threads of the beam nut. Periodically, the flexible holdout spring can become wedged and locked in two axial slots located on the inside diameter of the beam nut. Additional problems of prior designs are that the locking torque was insufficient and manufacturing and fabrication operations were extremely high due to the slotting, tapping and subsequent retapping operations necessary to remove burrs. Consequently, an improved beam nut design is necessary to address these and other problems associated with prior beam nut configurations.